Merge pull request #1173 from JerziKaminsky/security_resolve_symlink

FOR_REVIEW: IPC security - Allow policy targets to be symlinks

1 files changed, 41 insertions, 0 deletions

diff --git a/common/util.c b/common/util.c
index 12ed0cdc..a9e6a9c2 100644
--- a/common/util.c
+++ b/common/util.c
@@ -1,3 +1,7 @@
+#define _XOPEN_SOURCE 500
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
 #include <math.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -118,3 +122,40 @@ uint32_t parse_color(const char *color) {
 	}
 	return res;
 }
+
+char* resolve_path(const char* path) {
+    struct stat sb;
+    ssize_t r;
+    int i;
+    char *current = NULL;
+    char *resolved = NULL;
+
+    if(!(current = strdup(path))) {
+           return NULL;
+    }
+    for (i = 0; i < 16; ++i) {
+        if (lstat(current, &sb) == -1) {
+           goto failed;
+        }
+        if((sb.st_mode & S_IFMT) != S_IFLNK) {
+            return current;
+        }
+        if (!(resolved = malloc(sb.st_size + 1))) {
+           goto failed;
+        }
+        r = readlink(current, resolved, sb.st_size);
+        if (r == -1 || r > sb.st_size) {
+           goto failed;
+        }
+        resolved[r] = '\0';
+        free(current);
+        current = strdup(resolved);
+        free(resolved);
+        resolved = NULL;
+    }
+
+failed:
+    free(resolved);
+    free(current);
+    return NULL;
+}
\ No newline at end of file